Chapter 8: Radioactivity
Cosmic Rays
Cosmic rays are
high-energy radiation
produced outside the
Solar System or from
another galaxy. These
cosmic rays are also
known as galactic
cosmic rays.
Photograph 8.1 Cherenkov telescope on Mount Hopkins, United States of
America used to detect cosmic rays
Background Radiation
Background radiation is made up of various types of ionising radiation in the environment.
Background radiation is released from various sources including natural sources and man-made
sources. Sources of background radiation include:
• cosmic rays
• radioactive radiation from natural radioactive substances in the surroundings
• radioactive wastes from nuclear accidents and nuclear tests
• radioisotopes from medical use
Unit of Dose Rate Measurement for Background Radiation
Ionising radiation that is absorbed into the human body will damage body cells. Due to
this, the biological effect from ionising radiation on human body is measured in a quantity
known as dose. A dose of 1 Sv is equivalent to 1 joule of
BRAIN
ionising radiation energy that is absorbed by 1 kilogram of TEASER
living tissue. The unit of background radiation dose that is
What is the meaning of 1 μSv/h?
commonly used is microSievert/hour (μSv/h).
(a) In the garden (b) In the school compound
Photograph 8.2 Measuring background radiation using a Geiger counter
Study and compare the readings of the dose rate of background radiation on a Geiger Counter
in Photograph 8.2. What is the unit of dose rate measurement for background radiation shown
in the readings on the counter?
8.3.3 243
Safe Background Radiation Dose in Daily Life
Background radiation
or ionising radiation SCIENCE INFO Websites
dose of less than
Safe level of background radiation
0.2 μSv/h is the Exposure to radiation in daily life
dose is:
normal level or • < 0.2 μSv/h
safe level. Based on • < 0.0002 mSv/h
Photograph 8.2, the • < 1 752 μSv/year
garden and school • < 1.752 mSv/year
compound are safe
areas because both areas have background radiation dose of http://links.andl17.com/BT_
less than 0.2 μSv/h. Science_244_2 and click
The estimation of dose rate of ionising radiation from “Radiation Level“
various sources in daily life are shown in Figure 8.11.
Identify which sources are safe for an individual.
TV/computer:
X-ray
t
O
space
u
er
:
Outer space: ionising radiation 5.5 mSv/medical
t
y
y
a
ra
r
cosmic
mic
cosmic rayss s 0.01 mSv/h test
0.35 mSv/year
0. 35 m Sv / / / ye a r
High altitude:
cosmic rays Smoking:
0.3 - 0.5 mSv/year radioactive
radiation
55 mSv/cigarette
Flight:
cosmic rays Building:
0.003 mSv/h radioactive radiation
Food: radioactive 1.5 mSv/year
radiation
Environment: 0.1 – 0.5 mSv/year
background radiation
0.4 – 1.0 mSv/year
Figure 8.11 Estimation of dose rate of ionising radiation
244 8.3.3
Chapter 8: Radioactivity
Risks from Exposure to Natural Ionising Radiation
Absorption of ionising radiation by the human body imposes health risks which are affected by
the dose of ionising radiation received. Several actions can be taken so that the ionising radiation
dose received does not exceed the safe level for the human body as shown in Table 8.5.
Table 8.5 Among the safety measures that need to be taken so that
the ionising radiation dose received does not exceed the safe level SCIENCE INFO
for the human body
Marie and Irene Curie are the
Source of only mother and daughter to
ionising radiation Safety measures have received three Nobel Prizes.
dose received Marie Curie received two Nobel
Prizes, which are Nobel Prize in
Background Use appropriate protective equipment Physics in 1903 and Nobel Prize
radiation such as spectacles fi tted with anti- in Chemistry in 1911. Irene Curie,
ultraviolet fi lm, anti-ultraviolet umbrellas Marie Curie’s daughter, received
and others her Noble Prize in Chemistry in
1935. Without realising the risks
Taking X-ray X-ray taken with doctor’s prescription
of being exposed to ionising
Television Ensure the distance between the radiation, they died of cancer
television and the viewer is at least caused by excessive exposure to
2 m. gamma rays during their research.
Food contaminated Do not eat food produced in areas
with radioactive contaminated with radioactive
substances substances such as fi sh from the
sea contaminated with radioactive
substances.
Cosmic rays Working hours of a pilot are limited to
a certain period of time because the
pilot is exposed to cosmic rays.
Activity 8.4
To interpret data on health risks related to the absorption level of
ionising radiation by the human body • ICS
• Simulation
Instructions activity
1. Work in groups.
2. Gather information from various sources on the health risks related to the absorption
level of ionising radiation by the human body.
3. Discuss the health risks to the human body due to absorption of the following doses
of ionising radiation in a year.
(a) Doses of 10 Sv.
(b) Doses in the range of 1 Sv to 10 Sv.
(c) Doses in the range of 0.1 Sv to 1 Sv.
(d) Doses of less than 0.1 Sv.
4. Share the outcome of your group discussion in class.
8.3.4 245
Examples of Absorption of Ionising Websites
Radiation Exceeding the Safe Level and
Safety Measures that Need to be Taken Safety measures for airline crew
members who are exposed to
As most cosmic rays are absorbed by the atmosphere, the
cosmic rays.
dose of cosmic rays on the surface of Earth is normally at
a value of less than 0.2 μSv/h, which is a normal or safe
level. The higher a person is from the surface of Earth, the
stronger the cosmic rays he receives. Name an example of a
career that involves working at high altitudes.
http://links.andl17.com/BT_
Science_246
Airline crew members such as
pilots (Photograph 8.3), stewards and
stewardesses normally receive cosmic
ray doses exceeding the safety level.
They are exposed to strong cosmic
rays in flights at high altitudes. Due
to this, their working hours in the sky
are limited to a certain period of time.
Photograph 8.3 Pilots
Formative Practice 8.3
1. (a) What is ionising radiation? Give one example of ionising radiation.
(b) What is non-ionising radiation? Give one example of non-ionising radiation.
2. Underline the correct answers.
(a) The ionising power of beta radiation is (higher/lower) than the ionising power of alpha
radiation but (higher/lower) than the ionising power of gamma ray.
(b) The penetration power of beta radiation is (higher/lower) than the penetration power
of alpha radiation but (higher/lower) than the penetration power of gamma ray.
3. (a) State two natural sources of ionising radiation.
(b) State three man-made sources of ionising radiation.
4. (a) State the unit of dose rate measurement for background radiation.
(b) What is 1 sievert (Sv)?
(c) What is considered a safe level of background radiation dose?
5. Why does the absorption level of ionising radiation for an individual working in the
aviation sector normally exceed the safety level?
6. A student watches television for 2 hours every day. Calculate the dose rate of ionising
radiation received by the student after 5 days. (Dose rate of ionising radiation from television
= 0.01 mSv/h)
246 8.3.4
Chapter 8: Radioactivity
8.
8.4 Uses of Radioactive Radiation
4
Radioactive Radiation in Daily Life
Radioactive radiation such as alpha radiation (α), beta radiation (β) and gamma ray (γ) are used
in various fields in daily life as follows:
Archeology and geochronology
Carbon dioxide in the air is made up of carbon-12
(C-12) which is stable and carbon-14 (C-14) which
is radioactive. As carbon dioxide is absorbed and
released by the body of living organisms, the
percentage of C-14 in the tissues of the organisms
does not change.
As soon as the organisms die, the amount of
C-14 in their tissues begins to decline because they
decay by emitting beta radiation with a half-life,
1
T , of 5 700 years. By measuring the activity of
2
C-14, the age of the remains can be determined.
This method is known as carbon-14 dating and
is used by archeologists or geochronologists to
Photograph 8.4 Dinosaur bones
determine the age of fossil and artifacts.
Monitoring the thickness of metal sheets
(Industry)
A thickness control device monitors the thickness of
metal sheets in factories. A metal sheet is passed in
between a beta radiation source and a beta radiation
detector. If the beta radiation detector detects too
much beta radiations, this means that the metal
sheet is too thin.
Photograph 8.5 Monitoring the
thickness of metal sheets
Agriculture
In agriculture, the rate at which beta radiation is
emitted during the nuclei decay of phosphorus-32
(P-32) is used to determine the absorption rate
of phosphate fertiliser in plants. Radioactive
radiation is also used to kill beetles, control the
population of pests by sterilisation, determine the
best type of phosphate fertiliser, and modify the
Figure 8.12 Determining the absorption
characteristics of plants.
rate of phosphorus-32 (P-32) fertiliser
8.4.1 247
Defence
Radioactive substances can be used in the field of defence such as the nuclear bomb. Besides
heat, radioactive radiation released from the explosion of a nuclear bomb destroys almost all
living things including humans and its effect exists for generations.
Today in history
T
oday in histor
y
On 20 September 2017, Malaysia
signed the ICAN agreement to ban
nuclear weapons at a United
Nations (UN) Conference.
Photograph 8.6 Atomic bomb explosion
Food preservation
The Radura logo in Figure 8.13 is used to label food preserved using radioactive radiation
such as gamma rays. Gamma rays are used in the preservation of food such as fruits to kill
bacteria in the food.
Figure 8.13 Radura logo Photograph 8.7 Preservation of food
using gamma rays
Medical
Gamma rays from caesium-137 (Cs-137) or
cobalt-60 (Co-60) are used to kill cancer cells.
Radioactive radiation is also used to determine
the location of blood clots using sodium-24
(Na-24), treat tumours in the brain using
technetium-99 (Tc-99), destroy germs using
cobalt-60 (Co-60) and treat thyroid glands using
iodine-131 (I-131).
Photograph 8.8 Gamma rays used
to treat cancer
248 8.4.1
Chapter 8: Radioactivity
Activity 8.5
To carry out a Gallery Walk on the use of radioactive radiation in
various fields • ICS
• Technology-
Instructions based activity
1. Work in groups. • STEM
2. Gather information from the Internet, print media and other electronic media on the
use of radioactive radiation in the areas of agriculture, defence, medicine, archeology
or geochronology, industry and food preservation.
3. Discuss the following:
(a) Types of radioactive radiation used
(b) Ways of using radioactive radiation
(c) Careers related to the use of radioactive radiation
4. Carry out the gallery walk activity.
Safe and Proper Handling of Radioactive Substances and
Radioactive Waste
Safety measures in the handling of radioactive sources and radioactive waste are shown in
Figure 8.14.
Storing radioactive sources Radioactive substances are Robotic hands are used to
or radioactive waste in shielded with thick slabs of handle radioactive substances
containers with thick lead lead. safely.
walls.
Wearing appropriate Detecting the dose rate
protective clothing when of radioactive radiation
handling radioactive absorbed into the body
Safety measures when
substances with detectors such as
bstances
handling radioactive radiation badges.
sources and
radioactive waste
Disposal of radioactive waste
done safely and properly
Figure 8.14 Safety measures in the handling of radioactive sources and radioactive waste
8.4.1 8.4.2 249
Appreciating the Importance of Websites
Radioactive Radiation
The importance of radioactive radiation for the well-being Handling the disposal of
of humans makes us grateful to the Almighty for creating radioactive waste safely and
properly
radioactive particles that have many uses to sustain life.
The first artificial radioactive element, phosphorus-30
(P-30), was created by Irene Joliot-Curie, the daughter
of Marie Curie. Since 1934, many artificial radioactive
elements have been produced by scientists. Artificial
radioactive elements cannot be produced without the
radioactive particles. http://links.andl17.com/BT_
Science_250
Formative Practice 8.4
1. State one example of the use of radioactive radiation in the following fields:
(a) Archeology and geochronology
(b) Medicine
(c) Agriculture
(d) Defence
(e) Industry
2. (a) State the type of radioactive radiation used in the preservation of food.
(b) How can this type of radioactive radiation preserve food?
3. Why are radioactive sources or radioactive waste kept in boxes with thick lead walls?
4. Figure 1 shows a warning symbol.
Figure 1
(a) What is the meaning of the warning symbol shown in Figure 1?
(b) Name one example of a place or area which displays this warning symbol.
(c) Among the three types of radioactive radiations, which is the least dangerous? Explain
your answer.
5. (a) State one metal that is used to make appropriate protective clothing to handle
radioactive substances.
(b) State one advantage and one disadvantage of using the metal to make the protective
clothing mentioned in 5(a).
250 8.4.2
Chapter 8: Radioactivity
Uses of radioactive radiation in fields such as Agriculture, defence, medicine, archeology, geochronology, industry, food preservation Safety measures 4UPSJOH PG SFTPVSDFT r 1SPUFDUJWF DMPUIJOH r 4IJFME JO MFBE CPY r 6TF PG SPCPUJD r hands 3BEJBUJPO CBEHFT r 4BGF BOE QSPQFS r disposal
Applying the understanding of the structure of atom in the Formation of positive and negative ions by Ionising radiation such as Alpha radiation, beta radiation, gamma ray and X-ray from Man-made sources such as nuclear tests and artificial radioactive elements
Radioactivity and nucleus Natural sources such as cosmic rays, background radiation
Decay process of unstable nucleus by emitting radioactive radiation Examples of radioactive substances C-14, Rn-222, Th-234, U-238 units of radioactivity becquerel (Bq), curie (Ci)
Summary Discovery of radioactivity Chronological order Wilhelm Roentgen who discovered X-ray (1895) Henri Becquerel who discovered radioactivity (1896) Marie and Pierre Curie who succeeded in detecting radioactivity through its ionising effects (1897)
251
Self-reflection
After studying this chapter, you are able to:
8.1 Discovery of Radioactivity
Describe the history of the discovery of radioactivity.
Explain with examples radioactive substances, radioactivity and the concept of half-life.
8.2 Atom and Nucleus
Draw an atomic structure in a stable state.
Explain the formation of positive ions and negative ions.
8.3 Ionising Radiation and Non-ionising Radiation
Describe ionising radiation and non-ionising radiation.
Differentiate the three types of ionising radiation in radioactive decay.
Explain with examples sources of ionising radiation in the environment, natural sources
and man-made sources.
Discuss ways to manage the risks from exposure to natural and man-made
ionising radiation.
8.4 Uses of Radioactive Radiation
Communicate the use of radioactive radiation for well-being.
Justify the importance of proper handling radioactive substances and radioactive waste.
Summative Practice 8
Answer the following questions:
1. Mark ‘✓’ for the correct statements and ‘×’ for the incorrect statements.
(a) Wilhelm Roentgen discovered the X-ray. ( )
(b) Henri Becquerel used the element radium in his investigations on radioactivity. ( )
(c) The death of Marie Curie is caused by the exposure to gamma rays. ( )
2. What is the meaning of radioactive decay?
3. Name the radioactive substance in the common salt used in the medical field.
4. Pa-234 decays to U-234 by emitting beta radiation. If the half-life of Pa-234 is 5.2 hours,
what is the remaining mass of Pa-234 after 20.8 hours given its original mass is 32 g?
252
Chapter 8: Radioactivity
5. Tables 1(a) and 1(b) show the formation of ions.
Table 1(a)
Magnesium atom, Mg Magnesium ion, Mg 2+
Subatomic particle Number Charge Subatomic particle Number Charge
neutron, n 12 0 neutron, n 12 0
proton, p 12 +12 loses two proton, p 12 +12
electrons
electron, e 12 –12 electron, e 10 –10
The charge on magnesium 0 The charge on magnesium +2
atom, Mg ion, Mg 2+
Table 1(b)
Fluorine atom, F Fluoride ion, F –
Subatomic particle Number Charge Subatomic particle Number Charge
neutron, n 10 0 neutron, n 10 0
gains one
proton, p 9 +9 proton, p 9 +9
electron
electron, e 9 –9 electron, e 10 –10
The charge on fluorine atom, F 0 The charge on fluorine ion, F – –1
(a) Is the ion formed in Table 1(a) a positive ion or negative ion? Explain your answer.
(b) Is the ion formed in Table 1(b) a positive ion or negative ion? Explain your answer.
H HOTS
T
T
T
T
T
T
T
T
T
S
S
S
S
S
S
S
S
S
H
H
H
H
H
H
Focus on HOTS
H
H
O
O
O
O
O
O
O
O
O
6. (a) State three similarities between X-ray and gamma ray.
(b) Figure 1 shows the condition of two samples of strawberries, X and Y, before and after
7 days.
Day one After 7 days Day one After 7 days
Sample of strawberries X Sample of strawberries Y
Figure 1
253
(i) Which sample has been preserved? Explain your answer.
(ii) What is the radioactive radiation used to preserve food?
(iii) How can this radioactive radiation preserve food?
(iv) Is food preserved using this radioactive radiation safe to be consumed?
Explain your answer.
7. (a) Figure 2(a) shows an activity that is normally carried out in a laboratory to study
radioactive substances.
Figure 2(a)
Based on the activity in Figure 2(a), describe the safety measures taken when handling
radioactive substances.
(b) Figure 2(b) shows an example of the use
Beta radiation Radiation
of beta radiation in an industry. source
Beta radiation is used to monitor the detector
volume of drink in bottles. Beta radiation Bottle of
drink
is directed towards the passing bottle
Conveyor
as shown in Figure 2(b). If the bottle is
belt
not filled sufficiently, the beta radiation
will pass through the bottle and is then
detected by a detector. The circuit attached
to the detector then removes the bottle. Bottles removed
You are required to create a model to show
the quality control system that monitors
Figure 2(b)
the volume of drink in bottles as shown in
Figure 2(b) using the materials below.
• LED
• Empty mineral water bottle
• Newspaper
• Mirror
254
THEME
4 Earth and Space
4
Exploration
The RazakSAT-2 satellite is a satellite
created entirely by local scientists. One
of the uses of this satellite is in the field
of defence.
Our life is affected by local
weather conditions. For
example, we will use an
umbrella on a rainy day.
What is the importance of
space weather?
255
Chapter r
Chapter
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9 9 9 9 9 9 9 9 9 9 9 Space Weather
1
What is the structure of the Sun?
What phenomena occur on the surface of the Sun?
What are the effects of space weather on Earth?
Let’s study
Let’s study
Activities of the Sun that affect Earth
Space weather
256
Science Gallery
The Sun’s X9.3 class solar flare at 8.02 am on
6 September 2017
On 6 September 2017, coronal mass ejections caused
disturbances to telecommunication, navigation system and
electric power lines for about an hour. What are the effects of
this phenomenon on daily life on Earth?
Keywords
Sun Corona
Core Solar flare
Radiation zone Sunspot
Convection zone Solar cycle
Photosphere Solar wind
Chromosphere Magnetosphere
Granule Prominence
257
9.1 Activities of the Sun that Affect Earth
9.
1
The Sun appears as a ball of How is helium
glowing gases as shown in produced in the
Sun?
Photograph 9.1. The Sun
consists almost entirely of
two types of gases, hydrogen
and helium.
MEI
Photograph 9.1 The Sun
Structure of the Sun
The structure of the Sun consists of the
parts shown in Figure 9.1. Carry out Convection zone
Activity 9.1 to learn more about the
structure of the Sun. Radiation zone
Corona Core
Three layers that form
the Sun’s atmosphere Chromosphere
Photosphere
Figure 9.1 Structure of the Sun
Activity 9.1
To gather and share information on the structure of the Sun
consisting of the core, radiation zone, convection zone, photosphere, • ICS, ISS
chromosphere and corona • Discussion
activity
Instructions
1. Work in groups.
2. Gather information from the Internet, printed media and other electronic media
on the structure of the Sun consisting of the core, radiation zone, convection zone,
photosphere, chromosphere and corona.
3. Discuss and share the information gathered.
4. Present the outcome of your group discussion using multimedia presentation.
258 9.1.1
Chapter 9: Space Weather
Phenomena that Occur on the
Science Careers
Surface of the Sun
A career as a solar scientist is
Phenomena that occur on the surface of the Sun include: relatively new in the field of solar
• Granules energy. Besides inventing solar
• Sunspots energy equipment, a solar scientist
• Solar cycles also studies and forecasts space
weather which greatly affects daily
• Prominences
life on Earth.
• Solar flares
• Coronal mass ejections
• Solar winds
Granules, Sunspots and Solar Cycle
Sunspot Granule
The photosphere in the Sun’s atmosphere is made
up of granules which appear as grainy structures.
The granules are the upper part of the convection
zone of the plasma which is extremely hot with
a temperature as high as 5 800°C. The
average diameter of a granule is
about 1 000 kilometres!
Sunspots are the dark regions
seen on the surface of the Sun as
shown in Figure 9.2. Sunspots appear
dark because their temperatures are
lower than their surrounding areas
which are made up of granules.
Sunspots are the locations of very
large eruptions in the photosphere.
This phenomenon may last more than
a week. Sunspots are phenomena that
always exist in pairs or groups.
The activity of the sunspots seems to
appear and disappear according to a cycle Figure 9.2 Granules and sunspots
that lasts 11 years known as the solar cycle.
Figure 9.3 shows the position of sunspots in
the photosphere since 1875.
60°N
30°N
Equator
30°S
60°S
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
(Source: NASA)
Figure 9.3 Position of sunspots on the surface of the Sun
9.1.1 259
Prominence
A prominence shown in Photograph 9.2 is a huge loop
or arched column of glowing gases over the sunspot.
Prominences can reach heights of hundreds of thousands
of kilometres and may last for several days or months.
Prominences that are very strong can throw out matter from
-1
the Sun into space at speeds ranging from 600 km s to
-1
more than 1 000 km s .
Photograph 9.2 Prominence
Solar Flares
A solar flare shown in Photograph 9.3 is a column of large
amounts of charged gases erupting from the Sun and often
occurs near sunspots. Solar flares are strong and spectacular
explosions of gases. Solar flares attain their maximum
brightness level within a few seconds or minutes and then
become dim after a few minutes or hours. Solar flares spout
charged gas particles at high speeds into outer space. The
light from solar flares which is at the speed of light takes
eight minutes to reach Earth while the charged gas particles
take tens of minutes.
Photograph 9.3 Solar flare
These charged gas particles often collide with atoms and
molecules in Earth’s atmosphere to produce a stunning light
display in the sky known as aurora which uniquely occurs
only in the air space around Earth’s poles.
Coronal Mass Ejections
A coronal mass ejection shown in Photograph 9.4 is a huge
cloud of plasma that erupts from the Sun and often occurs
together with solar flares which are huge and strong. A
coronal mass ejection is an ejection of magnetic gas particles. Photograph 9.4 Coronal mass ejection
The coronal mass ejection spouts magnetic particles at high
speeds into outer space and appears like an expanding cloud.
These magnetic particles from the coronal mass ejection take
three days to reach Earth.
Like the charged gas particles in solar flares, the magnetic
gas particles also react with atoms and molecules in Earth’s Watch a video on prominences,
atmosphere to produce aurora. solar flares and coronal mass
ejections.
:*(5
7(.,
260 9.1.1
Chapter 9: Space Weather
Solar Wind
Particles in plasma such as electrons, protons and
alpha particles that erupt from the Sun to outer
space travel together at high speeds known as
solar wind as shown in Photograph 9.5.
Solar wind also carries the interplanetary
magnetic field along with it. The speed of solar
wind is supersonic with values ranging from Earth
-1
-1
250 km s to 750 km s . However, the speed, Solar wind
temperature and density of the solar wind
changes along the course of its movement.
Photograph 9.5 Solar wind (in yellow)
Earth’s Magnetosphere and its Importance
Shape of Earth’s Magnetosphere
Magnetosphere
Solar wind Earth
Magnetosphere
(a) Earth’s magnetic field (b) Earth’s magnetosphere
Figure 9.4 Shape of Earth’s magnetosphere
Compare and contrast the pattern of magnetic field lines between Earth’s magnetic field and
Earth’s magnetosphere. Even though both of these patterns
of magnetic field lines are not fixed, the pattern of Earth’s
MARVELS OF
magnetic field lines changes slightly while the pattern of SCIENCE
the magnetic field lines in the magnetosphere changes a lot
Animation that shows
based on the interaction between solar wind and Earth’s
the relationship between
magnetic field.
magnetosphere and solar wind.
Definition of Earth’s Magnetosphere
Earth’s magnetosphere is defined as a region in outer
space surrounding Earth where the magnetic field in Earth’s
magnetosphere is a combination of Earth’s magnetic field
(as the prime magnetic field) and the magnetic field in the http://links.andl17.com/BT_
Science_261
region in outer space as shown in Figure 9.4(b).
9.1.2 261
Formation of Earth’s Magnetosphere
Magnetosphere is formed by the interaction between the magnetic field brought by the solar
wind and Earth’s magnetic field. As the number and energy of particles brought by the solar
wind change, the shape of the magnetosphere also changes.
Importance of Earth’s Magnetosphere
The importance of magnetosphere is to protect Earth from the adverse effects caused by
dangerous particles from the Sun or other bodies in the Universe.
Magnetosphere
(magnetic field lines
Solar wind in blue)
(in yellow)
Earth protected
by magnetosphere
Magnetosphere
(magnetic field lines
in blue)
Figure 9.5 Protection from Earth’s magnetosphere
The magnetosphere:
• functions as a biological shield to protect life on Earth from the adverse effects of solar wind
• blocks charged particles such as electrons, protons and alpha particles in the solar wind from
reaching Earth. Excessive numbers of charged particles in Earth’s atmosphere will disrupt
telecommunication, navigation system and electric power lines
• reduces the pressure exerted by solar wind on Earth’s atmosphere
Activity 9.2
To gather and share information on the definition, formation, shape
and importance of the magnetosphere • ICS, CPS, ISS
• Discussion
Instructions activity
1. Work in groups.
2. Gather information from the Internet, printed media and other electronic media on
the definition, formation, shape and importance of the magnetosphere.
3. Discuss and share the information gathered.
4. Brainstorm on the condition of Earth without the magnetosphere.
5. Present the outcome of your group discussion using multimedia presentation.
262 9.1.2
Chapter 9: Space Weather
Formative Practice 9.1
1. State three structures of the Sun that form the Sun’s atmosphere.
2. State three phenomena that occur on the surface of the Sun where charged gases erupt.
3. Define Earth’s magnetosphere.
4. What influences the shape of the magnetosphere?
5. Name one object in the Solar System that has the same shape as solar wind.
9.
2
9.2 Space Weather
Space Weather and its Effect on Earth Websites
Space weather is defined as the phenomena that occur:
• on the surface of the Sun such as solar flares, Space weather
prominences, sunspots and coronal mass ejections
• in space such as solar wind, solar radiation storm and
geomagnetic storm
http://links.andl17.com/BT_
Science_263
Study Figure 9.6. Then, carry out Activity 9.3.
Sunspot Coronal mass ejection Magnetic field
line
Solar wind
Solar radiation storm Earth
Earth Magnetic field
line
Solar flare
Geomagnetic storm
Figure 9.6 Space weather
9.2.1 263
Activity 9.3
To gather and share information on the definition of space weather
and its effects on Earth • ICS, CPS, ISS
• Discussion
Instructions activity
1. Work in groups.
2. Gather information from the Internet, printed media and other electronic media on
the definition of space weather and effects on Earth such as the formation of the
aurora, disturbances to telecommunication, navigation system as well as electrical
power lines.
Space storms Effects of geomagnetic
http://links.andl17.com/ storm, solar radiation
BT_Science_264_1 storm and disturbances
of radio transmission
http://links.andl17.com/
BT_Science_264_2
3. Discuss and share the information gathered.
4. Present the outcome of your group discussion using multimedia presentation.
Interpretation of Data on Space Weather
Data on space weather is used or analysed to:
• forecast when coronal mass ejections occur in the Sun
• determine the reasons for the occurrence of solar flares and coronal mass ejections on the
surface of the Sun
Activity 9.4
To interpret data on space weather
• ICS, CPS, ISS
Instructions • Discussion
1. Work in groups. activity
2. Gather information or data on space weather from the Internet,
printed media and other electronic media.
Sources of solar wind in relation to solar cycle
http://links.andl17.com/BT_Science_264_3
3. Interpret data on space weather by relating the number of sunspots or solar cycles
with the increase in coronal mass ejections and solar winds.
4. Present your group’s interpretation of space weather data using multimedia presentation.
264 9.2.1
Chapter 9: Space Weather
Formative Practice 9.2
1. What is the definition of space weather?
2. State four examples of the effects of space weather on Earth.
3. What is the relationship between the number of sunspots and the increase in coronal
mass ejections?
Summary
Space weather
is influenced by
Sun Solar wind Phenomena on the
surface of the Sun
which determines the shape of the
produce effects
such as
Structure Phenomena on Magnetosphere Formation of aurora,
its surface
disturbances to
such as which telecommunication,
Core, radiation navigation system as well
zone, as electric power lines
convection Granules, Protects
zone, prominences, Earth which shows
photosphere, solar flares,
chromosphere, solar cycles, from
corona The relationship
sunspots,
coronal mass Adverse effects between the number of
ejections, from harmful sunspots (solar cycle),
solar winds and the increase in
particles in coronal mass ejections
solar winds and solar winds
265
Self-reflection
After studying this chapter, you are able to:
9.1 Activities of the Sun that Affect Earth
Explain the structure of the Sun and phenomena that occur on the Sun's surface
by drawing.
Justify the importance of Earth’s magnetosphere.
9.2 Space Weather
Communicate space weather and its effects on Earth.
Summative Practice 9
Answer the following questions:
1. Figure 1 shows the structure of the Sun.
A: D:
B: E:
C:
F:
Figure 1
Name the structures labelled A to F using the following words:
Photosphere Corona Chromosphere
Core Convection zone Radiation zone
2. What is the duration of one solar cycle?
3. State the phenomenon related to solar cycle.
266
Chapter 9: Space Weather
4. State three examples of equipment or service used daily which is disrupted by solar
winds.
5. What would happen to the condition of Earth if there is no magnetosphere?
Explain your answer.
Focus on HOTS
6. Earth’s magnetosphere shown in Figure 2, is a region in space which protects Earth.
Figure 2
The shape of Earth's magnetosphere is produced by the interaction between Earth’s
magnetic field and solar wind. Magnetic field lines from other planets in the Solar System
are represented by white lines while Earth’s magnetic field lines are represented by red lines
as shown in Figure 2.
You are required to create a model of the magnetosphere using the following materials:
Green-coloured plastic bag
• Green-coloured plastic bag
White thread
• White thread
Red thread
• Red thread
Polystyrene cup with a convex cover
• Polystyrene cup with a convex cover
Plasticine
• Plasticine
Sketch the model of the magnetosphere. Explain how the model functions.
267
Chapter
Chapter
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10 10 Space Exploration
0 0
1
How can the model of the Solar
System be improved from time
to time?
Give three examples of
technological invention devices
applied in space exploration.
Give an example of the use of
remote sensing technology in
field of geology.
Let’s study
Let’s study
Development in astronomy
Development of technology and its application in space exploration
268
Science Gallery
International Space Station, ISS
n
is a
ISS
)
(
The International Space Station (ISS) is a
station that facilitates international research
na
h
l
researc
o
at
i
t
in space. The function of this stationn
e
and
is to carry out research in space and
monitor space.
Dato’ Dr Sheikh
Muszaphar Shukor Al Masrie
bin Sheikh Mustapha is the
first astronaut from Malaysia
to carry out experiments in
space from 10 October to
21 October 2007.
Keywords
Geocentric Satellite
Heliocentric Space probe
Kepler’s Law Remote sensing
Ellipse Geology
Focal point Disaster management
Rocket Space Telescope
269
10 . 1 Development in Astronomy
10.1
Historical Development of the Solar System Model
Study Figure 10.1. Then, carry out Activity 10.1.
History of the Solar System Model
Ptolemy Copernicus
o " % o
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t #VJMU UIF geocentric NPEFM XJUI UIF 4VO BU
NPEFM XJUI &BSUI BU UIF DFOUSF BOE DJSDVMBS
UIF DFOUSF BOE PSCJUT
DJSDVMBS PSCJUT
Geocentric model Heliocentric model
Jupiter
Mercury
Jupiter Mars
Mars
Venus Saturn
Earth Mercury
Moon Sun
Venus Earth
Moon
Sun
Saturn
t A(FP NFBOT &BSUI
t A$FOUSJD NFBOT DFOUSF t A)FMJP NFBOT UIF 4VO
t &BSUI JT BU UIF DFOUSF PG UIF 4PMBS 4ZTUFN t A$FOUSJD NFBOT DFOUSF
t &BSUI JT TUBUJPOBSZ BOE BMM UIF PCKFDUT TVDI BT t 5IF 4VO JT BU UIF DFOUSF PG UIF 4PMBS 4ZTUFN
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&BSUI JO DJSDVMBS PSCJUT UIF 4VO JO B DJSDVMBS PSCJU
Figure 10.1 History of the Solar System model
270 10.1.1
Chapter 10: Space Exploration
Kepler
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BOE BTUSPMPHFS
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UIF 4VO BU POF DPNNPO GPDBM QPJOU PO
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Modified Heliocentric model according to Kepler’s Law
8 5
6
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10.1.1 271
Activity 10.1
To understand the development of the Solar System models built by
Ptolemy, Copernicus and Kepler • ICS
• Discussion
Instructions Activity
1. Work in groups.
2. Carry out active reading by visiting websites or going on a study tour to the National
Planetarium to gather information on the development of the Solar System models
built by:
(a) Ptolemy
(b) Copernicus
(c) Kepler
Examples of websites are as follows:
Watch these sections Historical attempts to
of the video model the Solar System
3.01 Historical Solar (Take a challenge)
System Models http://links.andl17.com/
3.02 Current Solar BT_Science_272_2
System Model
http://links.andl17.com/
BT_Science_272_1
History of the Solar System model
http://links.andl17.com/BT_Science_272_3
3. Discuss and present to the class how knowledge gained through scientific research is
the product of human effort to obtain rational explanations about natural phenomena.
4. Present the outcome of your group discussion using multimedia presentation.
Formative Practice 10.1
1. Name the Solar System model built by the following astronomers:
(a) Ptolemy
(b) Copernicus
(c) Kepler
2. Compare and contrast the Solar System models built by Ptolemy and Copernicus.
(a) Similarities
(b) Differences
3. Compare and contrast the Solar System models built by Copernicus and Kepler.
(a) Similarities
(b) Differences
272 10.1.1
Chapter 10: Space Exploration
Development of Technology and its
10
10.2 Application in Space Exploration
2
.
Development in Space Exploration
Figure 10.2 shows part of the early history of space exploration in terms of technology
development and missions in space exploration.
2011: Construction of International 2002: National Space 2000:
Space Station (ISS) completed Agency (Agensi Angkasa Malaysia’s
Negara) established first
microsatellite
TiungSAT-1
launched
1990: US launched
Hubble Space Telescope 1996: Malaysian
1989: First Neptune satellites MEASAT 1
flyby – US Voyager 2 from space shuttle and 2 launched
1981: First Discovery
flight of US
space shuttle
– Columbia
1973: First Jupiter flyby – US 1969: First human to 1961: First human to orbit Earth –
Pioneer 10 set foot on the Moon – Yuri Gagarin, aboard USSR Vostok 1
Neil Armstrong,
US Apollo 11
1957: First satellite – USSR Sputnik 1
1609: First telescope used in the
11th century: field of astronomy by Galileo Galilei
Chinese invented
gunpowder and
used primitive
rockets in battles
Figure 10.2 Some of the events related to the development of technology
in space exploration
10.2.1 273
Applications of Technology in Space Exploration and their
Importance
Space Telescope
Figure 10.3 shows the development of the telescope.
The astronomical sextant is Galileo’s Telescope became Hubble space telescope
used to measure the altitude the most widely used was placed in an orbit 500 km
of stars astronomical instrument from the surface of Earth
The Spitzer space telescope
detects very distant activities
in space.
Apart from optical telescopes, radio
telescopes are also used to detect radio
waves from space.
Figure 10.3 Space telescopes
Rocket
Rockets are used widely in space
explorations. When the fuel in a rocket
burns, hot gases are released at high speed
through the bottom of the rocket. The
release of these gases produces a force
which pushes the rocket upwards.
Vostok K Redstone Atlas Voskhod Titan II Soyuz Saturn 1B Saturn V STS Long Falcon SLS Angara Atlas V
March 2F 9 5P
Photograph 10.1 Rockets used to send humans to space
Based on Photograph 10.1, which rocket was used to send astronauts to the Moon?
274 10.2.1
Chapter 10: Space Exploration
Satellite
Websites
The first satellite,
Sputnik 1 was sent to
Satellite launch
outer space in 1957.
How many satellites are
orbiting around Earth
today? Which country
has the largest number
of satellites?
Photograph 10.2 Weather http://links.andl17.com/BT_
satellite GOES-16 gathers Science_275
data on solar flares
Space Probe
MARVELS OF
A space probe is a spacecraft SCIENCE
that gathers information and
In 2017, space probe Cassini was
sends it back to Earth. Space still active orbiting Saturn even
probes do not orbit Earth like after 20 years in space.
satellites but travel further
into and out of the Solar
Photograph 10.3 Space
System. Space probes carry
probe Cassini
cameras and remote sensing
instruments as well as radio
transmitters and receivers for the purpose of
communicating with scientists on Earth.
Remote Sensing
Remote sensing is a method of gathering and recording information from a distance. In
Malaysia, remote sensing instruments are fitted to TiungSAT-1 to receive or detect visible,
ultraviolet and infrared lights produced by objects on the surface or below the surface of
Earth. The information gathered by TiungSAT-1 is then sent to two data receiving stations at
the National Planetarium Station, Federal Territory of Kuala Lumpur and the Mission Control
Station (MCGS), Bangi, Selangor.
Photograph 10.4 shows the pattern and movement of
clouds taken from TiungSAT-1’s remote sensing camera.
What is the use of the information obtained from this
photograph?
Remote sensing technology is used in various fields in
daily life as follows:
• Agriculture – To detect suitable regions for agricultural
development
• Geology – To detect locations such as mineral sources,
mass depletion and land depletion Photograph 10.4 A picture of
• Disaster management – To identify pollution and forest fires the pattern and movement of
• Defence – To detect intrusions of enemy ships, aircraft and clouds
vehicles
10.2.1 275
Activity 10.2
To understand the development of technology in space exploration
• ICS
Instructions • Discussion
1. Work in groups. activity
2. Carry out active reading by visiting websites or going on a study
tour to the National Planetarium, MACRES and National Space Agency to gather
information on the development of technology in space exploration in:
(a) early history of space exploration
(b) the construction of rocket, satellite and space probe
(c) remote sensing used in agriculture, geology, disaster management and defence
3. Discuss and present the development and technological applications in space
exploration and their importance.
4. Present the findings of your group discussion using multimedia presentation.
Activity 10.3
To debate the issue of continual space exploration
• ISS, CPS
Instructions • Project-based
1. Work in groups. activity
2. Gather information from the Internet, printed media and other
electronic media on the importance of space exploration in the local and global
context.
3. Share and discuss the gathered information.
4. Debate the issue of continual space exploration in the local and global context.
Formative Practice 10.2
1. Name the first technological device used in space exploration.
Hape
2. Study Figure 1.
(a) What is Discovery?
(b) What is Hape?
3. (a) Name the technology used to take aerial photographs.
(b) What is the importance of taking aerial photographs Discovery
during floods?
4. What is the role played by the Malaysian Remote Sensing Agency
(MACRES)?
Figure 1
276 10.2.1 10.2.2
Chapter 10: Space Exploration
Space probe used to Gather and send information on distant bodies in space
Development of technology and its application in space exploration such as Satellite used to Gather information on space weather, remote sensing, telecommunication, defence Remote sensing used in Agriculture, geology, disaster management, defense
Space exploration is infuenced by Rocket used to Send spaceships, satellites, space probes to space
Kepler Sun as the centre of the Solar System with Earth and other planets revolving in elliptical orbits
Development in astronomy such as Building of solar system models by Copernicus Sun as the centre of the Solar System with Earth and other planets revolving in circular orbits
Summary Ptolemy Earth as the centre of the Solar System with Sun and other planets revolving in circular orbits
277
Self-reflection
After studying this chapter, you are able to:
10.1 Development in Astronomy
Explain the historical development of the Solar System model by drawing.
10.2 Development of Technology and its Application in Space Exploration
Communicate the importance of the development of technology and its application in
space exploration.
Justify the need to continue space exploration.
Summative Practice 10
Answer the following questions:
1. Figure 1 shows the Spitzer space telescope.
Figure 1
Mark ‘✓’ for the correct statements and ‘×’ for the incorrect statements.
(a) The Spitzer space telescope is located on the surface of Earth.
(b) The Spitzer space telescope ‘observes’ better than ordinary telescopes.
(c) The Spitzer space telescope is used to take photographs of Earth’s
surface.
(d) The Spitzer space telescope is used as a remote sensing equipment.
278
Chapter 10: Space Exploration
2. Match the Solar System model to the astronomer who built it.
Solar System model Astronomer
(a) Earth is at the centre of the
Solar System and the Sun Copernicus
revolves around Earth in a
circular orbit.
Kepler
(b) The Sun is at the centre of
the Solar System and Earth
revolves around the Sun in Ptolemy
an elliptical orbit.
3. How can knowledge about astronomy be acquired through scientific investigation?
4. Why are space probes not used to send astronauts into space?
5. Figure 2 shows a space probe sent to Saturn.
Figure 2
(a) What is the function of this space probe?
(b) State one example of a phenomenon that occurs on the surface of the Sun that might
destroy the space probe.
(c) State the source of energy used by the space probe.
6. State two examples of the use of remote sensing technology in the following fields:
(a) Agriculture
(b) Geology
(c) Disaster management
(d) Defence
279
H HOTS
T
T
T
T
T
O
O
O
T
O
O
S
S
S
S
S
S
T
T
T
S
S
S
O
H
H
H
H
Focus on HOTS
H
H
H
H
O
O
O
7. Figure 3 shows a rocket.
Figure 3
(a) What is a rocket?
(b) What is the function of rocket in space exploration?
(c) Explain one misuse of rocket in our daily life.
8. Astronomers have successfully discovered three planets revolving around the TRAPPIST-1
star which are suitable for all life on Earth.
As these three planets are extremely far, a special spacecraft needs to be invented to
transfer life on Earth to these planets.
You are required to invent a model of the spacecraft using the following materials:
• Cardboard
• Cellophane tape
• Black plastic sheet
• Aluminium foil
280
ANSWERS
CHAPTER 1 Stimuli and Formative Practice 1.1 (p. 10)
Responses 1. Central nervous system and peripheral
nervous system
Activity 1.1 (p. 7) 2. (a) Voluntary actions are conscious
Questions actions, carried out according to the
1. Stimulus: Seeing your partner let go of wishes of a person and are controlled
the ruler.
Response: Catching the ruler using your by the brain.
Examples of controlled actions are
thumb and index finger. reading, writing, speaking, eating,
This is a voluntary action drinking, walking, running, exercising
because it is a conscious and singing.
action and is made according (b) Involuntary actions are spontaneous
to the will of the individual actions that happen without being
who received the stimulus realised or thought of beforehand.
and is controlled by the brain.
2. The distance moved by the ruler shows Examples of uncontrolled actions
are heartbeat, breathing, peristalsis,
the time taken by the student to catch secretion of saliva and sneezing.
the ruler. The shorter the distance, the 3. Injured nerve cells in the human brain
faster the reaction time.
3. Different students usually have different are unable to interpret impulses from
affectors and cannot send impulses to
reaction time. Besides this, the reaction effectors. Due to this, a person who
time of an individual is not constant.
4. In the daily life of humans, reaction time sustained brain injury is unable to carry
out voluntary or involuntary actions
plays an important role to coordinate and involving the brain.
control organs and body parts so that 4. The network of nervous system of
they function harmoniously and efficiently.
humans functions to control and
coordinate organs and body parts so as
Activity 1.3 (p. 9) to carry out processes in the body and
Questions daily activities.
1. Stimulus: Intensity of light that enters
the eye.
Response: Change in size of the pupil. Brain Teaser (p. 15)
This is an involuntary action Excess mucus is produced when a person
because this action occurs suffers from a cold. This excess mucus will
spontaneously without any obstruct receptors from being stimulated by
conscious control or prior chemical substances in the air entering the
thoughts. nasal cavity.
2. The higher the intensity of light, the
smaller the size of the pupil.
3. This response can help protect the eye Brain Teaser (p. 16)
from injury. A blind person uses the sensitivity of the
fingertip to read Braille and sensitivity of the
hand to detect vibrations of the walking stick
Brain Teaser (p. 10)
when it hits objects to detect any nearby
Muscular system obstructions.
1
Activity 1.6 (pp. 19, 20) substances in hot food also evaporate to
Questions form vapour which enters the nasal cavity
1. Tip of index finger. It has the largest and stimulates the smell sensory cells.
number of receptors. The combination of sense of taste and
2. Elbow. It has the least number of sense of smell causes hot food to taste
receptors. better.
3. Touch receptor.
4. Number of touch receptors and thickness Formative Practice 1.2 (p. 29)
of epidermis. 1. (a) Cornea
(b) Pupil
Activity 1.7 (p. 21) (c) Retina
Questions (d) Brain
1. To ensure no other solutions remain and 2. Semicircular canals
only the taste of one solution is detected 3. At the upper part of the nasal cavity
during each attempt. 4. Sweet, sour, salty, bitter, umami
2. All areas of the tongue can detect all 5. Number of receptors and thickness of
tastes of the solutions. skin epidermis
3. Both sides of the tongue are most 6. (a) Five types of taste, touch, pain, hot
sensitive towards taste because they objects, cold objects, and pressure.
have a large number of taste receptors. (b) Five types of taste can be detected
4. The middle part of the tongue is least by taste receptors in the taste
sensitive to taste because it has a small buds of the tongue. The tongue is
number of taste receptors. protected by skin that has touch,
5. The front part of the tongue is more pain, heat, cold and pressure
sensitive to sweet taste, the sides of receptors. Therefore, it can detect
the tongue are more sensitive to sour touch, pain, hot objects, cold objects
and sweet tastes, the back part of the and pressure.
tongue is more sensitive to bitter taste
and the middle part of the tongue is more Experiment 1.1 (pp. 30 – 33)
sensitive to umami. A. Questions (p. 31)
1. Light
Brain Teaser (p. 22) 2. Shoot of the plant
No. After the tongue is cleaned, the tongue 3. The shoot of the plant shows positive
will become more sensitive. phototropism because shoots of
plants grow towards the direction of
Activity 1.8 (pp. 22, 23) light.
Questions
1. Without the nose being pinched. B. Questions (p. 32)
2. Taste of the cordial drink is more easily 1. So that light cannot influence the
detected using a combination of sense of growth of the seedlings.
taste and sense of smell. 2. (a) Grow upwards against the
3. So that your partner does not use sense direction of gravity.
of sight to determine the taste of the (b) Grow downwards in the direction
cordial drink based on the colour such as of gravity.
purple for taste of grape, orange for taste 3. Roots of plants show positive
of orange, yellow for taste of mango and geotropism because the roots of
red for taste of strawberry. plants grow towards the direction of
4. In addition to chemical substances gravity. Shoots of plants show negative
in food which dissolve in saliva and geotropism because shoots of plants
stimulate the taste buds, chemical grow against the direction of gravity.
2
C. Questions (p. 33) cat received by both of Azman’s ears are
1. Water the same. The brain then informs Azman
2. Roots of the plant the direction of the cat making the sound.
3. Absorbs water and moisture in the air
in beaker Y Summative Practice 1 (pp. 41 – 43)
4. The roots of the plants show positive 1. (a) ×
hydrotropism because they grow (b)
towards water. (c) ×
(d)
Formative Practice 1.3 (p. 35) 2. P: Brain
1. (a) Tropism is a directed response of Q: Spinal cord
plants towards stimuli coming from a R: Peripheral nerve
certain direction. 3. (a) Changes in the size of the pupil of
(b) (i) Thigmotropism the eye.
(ii) Geotropism (b) Intensity of light which enters the eye.
(iii) Phototropism (c) The lower the intensity of light
2. (a) (i) Shoots directed towards the eye, the larger
(ii) Roots the size of the pupil of the eye.
(iii) Tendrils or winding shoots (d) During a solar eclipse, the bright
(b) Positive hydrotropism allows roots to rays of the sun will enter the eye and
obtain water and dissolved mineral damage the cells of the retina.
salts to survive. 4. (a) Sound → Earlobe → Ear canal →
3. Similarity: Tropism and nastic response Eardrum → Ossicles → Oval window
are responses of plants → Cochlea → Auditory nerve → Brain
towards stimuli. (b) Light → Cornea → Aqueous humour
Difference: Tropism is the directed → Pupil → Eye lens → Vitreous
response of plants towards humour → Retina → Optic nerve →
stimuli while nastic response Brain
is the response towards 5. (a) X: Touch receptor
stimuli without considering Y: Pain receptor
their direction. (b) Fingertip is more sensitive towards
touch stimuli compared to the palm
Brain Teaser (p. 37) of the hand.
The blind have a more sensitive sense of Fingertip has a thinner layer of
hearing. They make use of sound to detect epidermis and more touch receptors
location and estimate distance of nearby compared to the palm of the hand.
objects. (c) Agree. The tongue is a sensory
organ that has receptors known as
Formative Practice 1.4 (p. 39) taste buds on the surface of the
1. Stereoscopic and monocular vision. tongue which is protected by skin
2. Location of eyes on the head. epidermis.
3. Primary consumer has monocular vision. 6. (a) The sense of smell helps us to detect
Monocular vision has a wide field of danger such as leakage of gas that
vision and allows it to detect predators might occur in the science laboratory.
coming from various directions. For example, we can detect the
4. Stereophonic hearing allows us to presence of dangerous gases such
determine the direction of sound as chlorine and ammonia from their
accurately. smell.
5. Azman uses his stereophonic hearing (b) Dogs have a very sensitive sense
to determine the cat’s location. The time of smell because they have more
and loudness of the sound made by the sensory cells for smell than human
3
and are more efficient to analyse 3. To provide sufficient oxygen and
smell than human. eliminate carbon dioxide from the air.
7. (a) – Positive phototropism 4. (a) (i) Rib cage
– Positive hydrotropism (ii) Diaphragm
(b) Positive phototropism ensures shoots (iii) Trachea and bronchus
and leaves of plants obtain sufficient (iv) Lungs
sunlight to make food through (b) – A thin rubber sheet stretches more
photosynthesis. easily compared to a thick rubber
Positive hydrotropism allows roots sheet.
of plants to grow towards water so – Therefore, a thin rubber sheet is
that they can absorb water to enable more easily pulled downwards or
plants to carry out photosynthesis. pushed upwards.
8. (a) Stereoscopic vision (c) (i) Breathing in or inhaling
(b) The eagle is a predatory animal. (ii) Exhaling
Stereoscopic vision helps the (d) – The structure or volume of the
eagle to hunt its prey by accurately glass jar which represents the rib
determining the location of its prey. cage is fixed when the thin rubber
9. Explanation: sheet is pulled downwards or
– Fill the transparent plastic bottle with pushed upwards.
water. – While the structure and volume of
– It functions as a convex lens. the rib cage changes during the
– Place it on top of the newspaper. processes of inhaling or exhaling.
– Read the newspaper through it.
Formative Practice 2.2 (p. 56)
1. Difference in concentrations of oxygen
CHAPTER 2 Respiration
gas in the alveolus and blood capillaries.
Experiment 2.1 (pp. 50 – 52) 2. (a) When concentration of oxygen is
Question (p. 51) high, haemoglobin will combine
– The water level in the gas jar containing with oxygen chemically to form
inhaled air is higher. oxyhaemoglobin which is unstable.
– Composition of oxygen in inhaled air is (b) When concentration of oxygen is low,
higher than that in exhaled air. oxyhaemoglobin will decompose to
– Burning of candle using the oxygen in the form haemoglobin and oxygen.
gas jar causes water to enter to fill the 3. Glucose + oxygen → carbon dioxide +
space originally filled with oxygen. water + energy
4. Efficiency of exchanging oxygen in the
Question (p. 52) human body decreases at high altitudes.
– Limewater in the conical flask where Concentration of oxygen in the air at high
exhaled air was passed through turns altitudes is low. Due to this, the rate of
cloudy. diffusion of oxygen from the alveolus into
– Carbon dioxide in the exhaled air reacts the blood capillaries is also low.
with the limewater. 5. – Thickness of wall of alveolus and
blood capillary is one cell thick
Formative Practice 2.1 (p. 53) – The wall of alveolus is moist
1. (a) Trachea – Alveolus with large surface area
(b) Bronchus – Dense network of capillaries covering
(c) Bronchiole alveolus
2. (a)
(b) × Brain Teaser (p. 57)
(c) × Forests help to maintain the balance of oxygen
(d) × and carbon dioxide in the atmosphere.
4
Brain Teaser (p. 58) to this, the health of all systems in the
Smoking endangers the health of the smoker body especially the respiratory system is
and everyone in the vicinity of the smoker. maintained.
5. Not smoking, frequent exercise
Brain Teaser (p. 59)
Electric buses do not emit exhaust gases. Brain Teaser (p. 67)
Therefore, air pollution can be reduced. Organ of gaseous exchange.
Experiment 2.2 (pp. 62, 63) Brain Teaser (p. 71)
Questions Air is always moving from one region to
1. Cigarette tar another region. Therefore cooperation from
2. Cigarette smoke is an acidic substance the global society is required. Prevention in
because it changes the purple colour of only one region would not be effective.
litmus solution to red.
3. Ammonia, stearic acid, methane, butane, Formative Practice 2.5 (p. 72)
methanol, toluene, cadmium, arsenic, 1. Leaves, stem, aerial roots
acetone 2. P: Guard cell Q: Stomatal pore
3. (a) Stomata open during the day. Water
Formative Practice 2.3 (p. 63) diffuses into guard cells through
1. (a) Tar, pollen, haze and dust osmosis causing the guard cells to
(b) Sulphur dioxide, carbon monoxide, bend and open the stoma.
nitrogen dioxide (b) Stomata close at night. Water
2. Pollen diffuses out of guard cells through
3. (a) Pain during breathing osmosis causing the guard cells
(b) Blood in phlegm to straighten up and close the
(c) Frequent shortness of breath stoma.
(d) Wheezing sound when breathing (c) Stomata are closed on hot days
4. Lung cancer, emphysema, bronchitis, to prevent excessive loss of water
(any two) through transpiration.
5. A person who does not smoke but 4. Polluted air will reduce the amount of
who breathes in cigarette smoke from sunlight reaching the plants and reduce
smokers nearby. the rate of photosynthesis. Hence, the
growth and survival of plants will be
Formative Practice 2.4 (p. 66) jeopardised.
1. (a) Gills
(b) Trachea Summative Practice 2 (pp. 74 – 77)
(c) Moist outer skin 1. (a) Alveolus
2. Thin outer skin of frogs, dense network (b) Bronchus
of blood capillaries under the layer of (c) Nasal cavity
skin, very permeable to respiratory gases 2. P: Trachea
and moist. Q: Bronchus
3. Body cells of insects have a direct R: Alveolus
connection with the respiratory surface. 3. (a)
Oxygen that enters the tracheole diffuses (b)
directly into the cells while carbon dioxide (d)
diffuses out. 4. (a) higher
4. When we exercise, our rate of respiration (b) lower
increases. Higher rate of transport of 5. (a) Haemoglobin transports oxygen from
oxygen to body cells and higher rate of the red blood cell to body cells.
elimination of carbon dioxide from body (b) Oxyhaemoglobin easily decomposes
cells result in healthier body cells. Due into haemoglobin and oxygen when
5
it reaches body cells so that oxygen gaseous exchange
can diffuse into the cells. in the alveolus is
6. (a) Azura may be allergic to pollen. In reduced causing
Spring, more pollen is released from shortness of breath.
anthers. When Azura inhales air 8. – Stop smoking.
containing pollen, there is a higher To avoid harmful substances found
risk of her getting an asthma attack. in cigarette smoke from entering the
(b) Any place that is hazy and dusty. lungs and harming the respiratory
Examples: industrial areas, system.
construction sites and others. – Avoid places with polluted air.
Haze and dust also cause asthma To avoid inhaling air that contains
attacks in asthma patients. harmful substances such as cigarette
7. (a) – Thickness of the wall tar, carbon monoxide, sulphur dioxide,
– Moisture of the wall nitrogen dioxide, haze, dust and pollen
– Surface area which are harmful to the respiratory
– Network of capillaries system.
(b) (i) Asthma – Have proper exercise and lead a
Symptom: Shortness of breath healthy lifestyle.
Cause: Excessive release To maintain a healthy respiratory
of mucus on the system.
surface of alveolus 9. Users at the waiting areas will become
reduces the surface passive smokers if there are other users
area and rate of nearby who smoke. This is harmful to
gaseous exchange in their health.
the alveolus thereby 10. (a) Gaseous exchange is through
causing shortness of diffusion into cells.
breath. (b) The respiratory system of insects
(ii) Bronchitis is more effective than the human
Symptom: Shortness of breath respiratory system.
Cause: Inflammation of the (c) Gaseous exchange through direct
bronchus in bronchitis diffusion into the cells of insects is
patients caused easier, quicker and more efficient
by tar and irritants compared to gaseous exchange
in cigarette smoke through transport of gases by blood
reduces the rate of in the human body.
movement of air from 11. (a) Carbon monoxide
the nose to the lungs (b) When the air in a car which
through the bronchus. contains carbon monoxide is
This causes bronchitis inhaled, the carbon monoxide
patients to be combines with haemoglobin to form
frequently breathless. carboxyhaemoglobin. Therefore,
(iii) Emphysema a person in the car will not have
Symptom: Shortness of breath sufficient oxygen supply which can
Cause: The alveolus in be fatal.
3
emphysema patients 12. (a) (i) 3.0 dm
is damaged by (ii) 2.5 dm 3
dangerous substances (b) (i) 4.0 dm 3
in the air such as (ii) 3.0 dm 3
irritants in cigarette (c) The more active the activity that is
smoke. Hence, the performed, the larger the maximum
surface area for volume of the lungs. From the graphs
6
in Figures 3(a) and 3(b), the volume – toxic waste products that fail to be
of air in the lungs of runners X and Y eliminated from the body to the outside
increases when they are running. surroundings will poison and kill the
(d) Runner Y. organism.
Cigarette smoke which damages the
alveolus will reduce the maximum Activity 3.2 (p. 84)
volume of air in the human lungs. Fish
The maximum volume of air in the – Fish has a single blood circulatory system
lungs of runner Y is less, therefore where blood flows through the heart only
runner Y is a smoker. once in one complete cycle to the all the
(e) Increase in the maximum volume other parts of the body.
of the lungs increases the rate of – Fish’s heart has one atrium and one
respiration because the rate of ventricle.
gaseous exchange in the lungs is – Deoxygenated blood flows out from
increased. the heart to the gills where gaseous
exchange occurs in the capillaries of the
gills changing deoxygenated blood to
CHAPTER 3 Transportation
oxygenated blood.
Formative Practice 3.1 (p. 82) – Oxygenated blood flows from the heart to
1. The function of the transport system the whole body, changes into deoxygenated
is to carry substances needed by cells blood and flows back into the heart.
into organisms and eliminate waste
products from organisms to the outside Amphibians
surroundings. – Amphibians have an incomplete double
2. Examples of substances needed by cells: circulatory system where blood flows
Oxygen, nutrients through the heart twice in one complete
Examples of waste products eliminated cycle to the whole body.
from cells: – Amphibian’s heart has two atriums and
Carbon dioxide, water, urea one ventricle.
3. Importance of the functions of transport – Deoxygenated blood flows out from the
system in organisms are as follows: amphibian’s heart to the lungs and skin
– Transport system provides substances where gaseous exchange occurs in the
needed by cells such as oxygen and blood capillary walls in the lungs or under
nutrients which are used to produce the skin changing deoxygenated blood to
energy through the process of cellular oxygenated blood.
respiration. – Oxygenated blood flows from the heart to
– Transport system provides substances the brain and a mixture of oxygenated and
needed by plant cells such as carbon deoxygenated blood flows to all other parts
dioxide and water which are used to of the body except the lungs. Oxygenated
carry out photosynthesis. blood changes into deoxygenated blood
– Transport system also eliminates and flows back into the heart.
toxic waste products from the cells of
organisms to the surroundings. Reptiles
4. If the transport system of an organism – Reptiles have an incomplete double
cannot function well, circulatory system where blood flows
– cellular respiration cannot be carried through the heart twice in one complete
out. Without energy, living process cycle to the whole body.
cannot occur in the organism. – Reptile’s heart has two atriums and one
– food cannot be made by green plants ventricle with a structure which divides the
through photosynthesis. Without food, space in the ventricle into two separate
plants and animals will die. parts.
7
– Deoxygenated blood flows out from 2. Artery
the heart to the lungs where gaseous Transports oxygenated blood (except
exchange occurs in the walls of the the pulmonary artery)
blood capillaries in the lungs changing
deoxygenated blood to oxygenated blood. Capillary
– Oxygenated blood flows from the heart to Connects arteries to veins and is a place
the whole body except the lungs, changes of exchange of substances between cells
to deoxygenated blood and flows back into Vein
the heart. Transports deoxygenated blood (except
pulmonary vein)
Mammals and birds
– Mammals and birds have a double 3. Type of activity, gender, age, health
circulatory system where blood flows 4. Caring for our heart is important to
through the heart twice in one complete ensure continuity of our life.
cycle to the whole body.
– The heart of mammals and birds have two Brain Teaser (p. 99)
atriums and two ventricles. An individual who has blood type O can
– Deoxygenated blood flows out from donate blood to all individuals irrespective of
the heart to the lungs where gaseous their blood type because blood type O does
exchange occurs in the walls of the not have any antigens on its red blood cells.
blood capillaries in the lungs changing Formative Practice 3.3 (p. 101)
deoxygenated blood to oxygenated blood. 1. Red blood cells, white blood cells,
– Oxygenated blood flows from the heart to platelets and blood plasma
the whole body except the lungs, changes 2. Blood plasma
to deoxygenated blood and flows back into 3.
the heart. Blood group of
Blood group of recipient
donor
Brain Teaser (p. 91) A B AB O
Systolic pressure is produced when the A × ×
ventricle pumps blood out from the heart to B
the whole body. Blood coming out flows with × ×
high pressure. Diastolic pressure on the other AB × × ×
hand is produced when blood flows into the O
heart. Blood flows with lower pressure.
4. (a) To save lives
(b) Leukaemia, haemophilia
Experiment 3.1 (p. 92) 5. (a) A person of blood group O can
Questions donate blood to any individual
1. The more active the activity, the higher because the person has no A antigen
the pulse rate. and B antigen.
2. The rate of intake of oxygen and release (b) A person of blood group AB can
of carbon dioxide by body cells increases receive blood from any individual
while carrying out active activity. This because his plasma does not contain
causes the heart to beat more frequently antibody Anti-A or Anti-B.
and increases the pulse rate to transport (c) Blood bank is the place where blood
oxygen and carbon dioxide more efficiently.
is stored and retrieved.
6. (a) Hospitals, National Blood Centre
Formative Practice 3.2 (p. 95) (b) Road accidents, war
1. Blood circulatory system is a special 7. (a) Blood group AB
transport system in complex organisms (b) Presence of virus and other
which functions to transport nutrients, unwanted substances
respiratory gases and waste products.
(c) Prevents clotting of blood
8
Activity 3.8 (p. 110) Summative Practice 3 (pp. 116 – 120)
Questions 1. (a) PULSE
1. The eosin solution stains to form a (b) TRANSPIRATION
specific pattern in the leaves, stem and (c) CAPILLARY
roots of the plant. (d) PHLOEM
2. Xylem (e) HEART
3. Passage of water in plants is through a (f) ANTIGEN
transport tissue, namely xylem. 2. (a)
(b) ×
Activity 3.9 (p. 111) (c) ×
Questions (d) ×
1.
3. (a) Valve
Part that is swollen (b) Transport oxygenated blood
(c) (i) Blood vessel Q has thick walls to
withstand high blood pressure.
Part that is shrivelled (ii) Blood vessel R has walls which
are one cell thick to increase
the efficiency of exchange of
2. Passage of food in plants is through the substances between blood and
phloem.
body cells through diffusion.
4. (a) Oxygen, carbon dioxide, water,
Formative Practice 3.4 (p. 112) digested food, waste products
1. Transpiration is a process of loss of (b) Oxygen, carbon dioxide, water
water in the form of water vapour from (c) During the day, plant cells carry out
the surface of plants to the air through photosynthesis and produce oxygen.
evaporation. Hence, plant cells do not need
2. (a) vapour, liquid oxygen supply.
(b) xylem, phloem 5. (a) (i) dub
3. Light intensity, air humidity, temperature, (ii) lub
air movement (iii) systolic
4. Passage of water in xylem can be (iv) diastolic
detected with the use of dye because (b) Systolic pressure reading is higher
water is colourless. than diastolic pressure reading.
5. P: Phloem Systolic pressure reading is reading
Q: Xylem of blood pressure which is higher
R: Xylem when heart ventricle contracts to
S: Phloem force blood out of the heart to be
T: Xylem distributed to the whole body.
U: Phloem
Diastolic pressure reading is reading
Formative Practice 3.5 (p. 113) of blood pressure which is lower
1. Similarity: – Both are transport systems when heart ventricle slackens to
– Both transport water, facilitate blood flowing from the whole
nutrients and dissolved body back to the heart.
substances 6. (a) (i) Eric, Roy
– Both exist in complex (ii) Blood will coagulate.The victim
organisms may die.
Difference: Pick one of the differences (b) (i) Individual 2.
shown in Figure 3.31. This is because she fulfils the
2. Organisms cannot continue to live if they age condition of 18 years and
do not have a unique circulatory system above but less than 60 years.
according to their respective needs. She also fulfils the body mass
9
condition of more than 45 kg. CHAPTER 4 Reactivity of Metals
(ii) Pregnant women are not suitable Brain Teaser (p. 126)
to donate blood. Mineralogists usually use the name bauxite,
7. (a) Transports food civilians such as mine workers use the name
(b) Xylem or Y aluminium ore and scientists use the name
(c) (i) The part above the ring will aluminium oxide.
become swollen. Food collected
here cannot be transported to the Activity 4.1 (pp. 126, 127)
part below the ring because of Questions
the absence of X (phloem). 1. Carbon dioxide
(ii) The plant will dry up and die. 2. Flow the gas through limewater. If the
54 g limewater turns cloudy, the gas is carbon
8. Set A = = 0.3 g/min
180 mins dioxide. On the other hand, if the
36 g limewater does not turn cloudy, the
Set B = = 0.2 g/min
180 mins gas is not carbon dioxide.
9. (a) Badrul. He has the highest pulse rate 3. (a) Carbon dioxide
immediately after activity. (b) Carbon dioxide
(b) Azizah. Her pulse rate returns to its 4. (a) calcium chloride + carbon dioxide +
original rate after a time interval of 15 water
minutes after activity. (b) calcium oxide + carbon dioxide
10. (a) Location B. 5. Calcium, carbon, oxygen
Location A is not suitable for the Formative Practice 4.1 (p. 128)
growth of herbs. This is because of 1. Minerals are naturally occurring solid
the absence of light needed by herbs elements or compounds with definite
to carry out photosynthesis. crystalline structures and chemical
Location C is not suitable for the compositions.
growth of herbs. High temperature in 2. (a) Gold, silver, diamond or other mineral
this location will increase the rate of elements (Any one)
transpiration of the herbs. (b) Bauxite, hematite, galena, cassiterite,
Location B is suitable for the growth quartz or other natural mineral
of herbs. Temperature in this dim compounds (Any one)
location is able to maintain the rate 3. Calcium oxide that has properties of a
of transpiration of the herbs. In base is used to neutralise acidic soil.
addition, the presence of sunlight in Silicon dioxide that has a high melting
the bright location enables the herbs point is used to make glass laboratory
to carry out photosynthesis. apparatus.
(b) Example of constructed model
Activity 4.3 (pp. 130, 131)
Transparent umbrella which Questions
can reduce the intensity of 1. (a) Magnesium oxide
light that enters (b) Aluminium oxide
(c) Zinc oxide
(d) Iron oxide
(e) Lead oxide
Tissue 2. The more reactive the metal towards
oxygen, the more vigorous the reaction.
3. Magnesium → Aluminium → Zinc → Iron
→ Lead
Brain Teaser (p. 132)
Water Carbon + oxygen → carbon dioxide
Device to regulate air humidity Hydrogen + oxygen → water
10
Activity 4.4 (pp. 132, 133) (b) Air pollution. Air pollution can be
Questions avoided by filtering the gases
1. (a) Zinc + Carbon dioxide produced before releasing them to
(b) No change the atmosphere.
(c) Lead + Carbon dioxide
2. Zinc and lead. Summative Practice 4 (pp. 143 – 145)
Oxides of metals which are less reactive 1. (a) Elements: Iron, Silver, Potassium,
than carbon will turn into the metals Tin
when heated with carbon. Compounds: Quartz, Bauxite,
3. Galena, Hematite, Limestone
Aluminium
Increasing Carbon (b) Bauxite, Aluminium and oxygen
reactivity Zinc 2. (a) Tin(IV) oxide
Lead (b) Carbon
(c) Tin + oxygen → Tin(IV) oxide
4. Metal extraction. Metals which are less 3. (b)
reactive than carbon in the reactivity (c)
series of metals can be extracted from 4. (a) Oxygen
their ores through the reduction of the (b) Potassium and sodium are very
oxide of these metals by carbon. reactive metals. Paraffin prevents
5. (a) more potassium and sodium from reacting
(b) less with oxygen and water vapour in the
Formative Practice 4.2 (p. 136) air.
1. The reactivity series of metals is an 5. (a) Oxygen
arrangement of metals according to their (b) To provide oxygen for the reaction.
reactivity towards oxygen. (c) Heat the powdered metal until it
2. (a) Yes. Metal X is reactive towards glows before heating potassium
oxygen because metal X burns with a manganate(VII) to provide oxygen for
bright flame. the reaction.
(b) Metal Y is less reactive than metal X. (d) To construct a reactivity series of
metals.
(c) X 6. For metals which are more reactive
Y than carbon, extraction of the metals
Z is through the electrolysis method. For
3. (a) oxygen metals which are less reactive than
(b) potassium carbon, extraction of the metals is
(c) extraction through reaction of the metal ores with
4. (a) Potassium carbon.
(b) Gold 7.
5. (a) Carbon and hydrogen
(b) Carbon and hydrogen can react with Mixture of iron
oxygen. powder, limestone
powder and coke Bottle/Plastic bag
Formative Practice 4.3 (p. 141)
1. (a) Electrolysis Air at room Drinking
(b) Reduction of iron ore with carbon temperature straw
2. (a) Tin Air at room
(b) (i) Iron ore, limestone, coke Hot air Cooking oil Hot temperature
(ii) Hot air Fan air
(c) (i) Slag blade Motor
(ii) Molten iron Motor Water
3. (a) Soil erosion. Problem of soil erosion Paper clip
can be solved by replanting trees.
11
Explanation: – Reaction between sodium hydrogen
carbonate and hydrochloric acid
Substance Represent 6. (a) Wrapping the polystyrene cup with
Bottle Blast furnace cotton wool or felt cloth, using a lid
for the cup.
Cooking oil Slag (b) Heat insulators such as cotton
wool and felt cloth and lid for cup
Water Molten iron reduces the transfer of heat to the
Motor Heating device surroundings.
Iron powder Iron ore Formative Practice 5.1 (p. 154)
1. (a) An endothermic reaction is a
Limestone powder Limestone
chemical reaction that absorbs heat
from the surroundings.
Innovative step: Fan blade is connected (b) An exothermic reaction is a chemical
in a direction opposite reaction that releases heat into the
to the normal direction surroundings.
so that sucked air flows 2. Thermochemistry is the study of heat
through the motor to be changes when chemical reactions occur.
heated. Motor is also 3. The rate of respiration increases when
cooled by this flow of performing vigorous physical activities,
air.
because respiration is an exothermic
reaction. Heat produced by the exothermic
CHAPTER 5 Thermochemistry reaction is absorbed into the body. Hence,
the body temperature increases.
Experiment 5.1 (pp. 149 – 151) 4. (a) Global warming
Questions (p. 151) (b) Reduce burning of fossil fuels.
1. (a) Release of heat is shown by the rise 5. (a) Exothermic reaction.
in thermometer reading. (b) Exothermic reactions release heat
(b) Absorption of heat is shown by the into the surroundings and increase
drop in thermometer reading. the temperature. High temperatures
2. (a) Thermal equilibrium can relieve muscle cramp.
(b) When the net rate of heat transfer
between the products of reaction
and thermometer is zero, products Summative Practice 5 (pp. 155 – 158)
of reaction and thermometer is 1. (a) Exothermic reaction
in thermal equilibrium. Hence, (b) Endothermic reaction
the temperature reading on the (c) Exothermic reaction
thermometer is fixed at maximum (d) Endothermic reaction
value or minimum value. (e) Exothermic reaction
3. (a) The temperature during reaction is (f) Exothermic reaction
higher than the temperature before 2. (a) released
reaction occurred. (b) increases
(b) The temperature during reaction is (c) hot
lower than the temperature before (d) absorbed
reaction occurred. 3. (a) THERMOCHEMISTRY
4. – Sodium hydroxide dissolving in water (b) PHOTOSYNTHESIS
– Reaction between sodium hydroxide (c) RESPIRATION
and hydrochloric acid (Neutralisation) (d) THERMOMETER
5. – Ammonium chloride salt dissolving in (e) ENDOTHERMIC
water (f) EXOTHERMIC
12
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